Wegovy can stay out of the refrigerator for up to 28 days, as long as it’s stored between 46°F and 86°F (8°C to 30°C) and the pen cap hasn’t been removed. After 28 days at room temperature, or if the pen has been exposed to temperatures outside that range, it should be thrown away.
The 28-Day Rule
Wegovy pens are meant to live in the refrigerator at 36°F to 46°F (2°C to 8°C). But the manufacturer, Novo Nordisk, allows a 28-day window outside the fridge for situations where refrigeration isn’t available. This covers everything from an overnight left on the counter to a two-week vacation.
There are three conditions that must all be met during those 28 days. The temperature needs to stay between 46°F and 86°F. The pen must be kept away from direct light (stored in its original carton). And the pen cap must not have been removed yet. Once any of those conditions is broken, the clock changes or the pen may no longer be safe to use.
The 28-day count is cumulative. If your pen sat out for 10 days, went back in the fridge, and then came out again, those first 10 days still count. You’d have 18 days of room-temperature time remaining, not a fresh 28.
Why Temperature Matters
Semaglutide, the active ingredient in Wegovy, is a peptide, a chain of amino acids that holds a specific shape to work in your body. Heat breaks that shape apart. Lab research has shown that when semaglutide is exposed to elevated temperatures, it degrades into over a dozen breakdown products that won’t have the intended effect. The warmer the environment and the longer the exposure, the more the drug deteriorates.
This is why the 86°F ceiling is firm. A pen left in a hot car on a summer day, where interior temperatures can easily reach 120°F or higher, isn’t safe to use even if it’s only been a few hours. The same applies to a pen stored near a window in direct sunlight or left in a checked suitcase in an airplane cargo hold.
What Happens if It Freezes
Freezing is just as damaging as overheating. If a Wegovy pen freezes, even briefly, don’t try to thaw it and use it. The medication may look normal after thawing but can lose its effectiveness. Throw it away and use a new pen. This applies to pens stored too close to the back wall or cooling element of a refrigerator, which can sometimes drop below freezing.
How to Tell if a Pen Has Gone Bad
Before every injection, look through the pen window. The solution should be completely clear and colorless. If it looks cloudy, discolored, or contains particles, don’t use it. These visual changes indicate the peptide has degraded. That said, a pen can lose potency without any visible change, which is why sticking to the temperature and time limits matters even when the liquid looks fine.
Traveling With Wegovy
A 28-day room-temperature window gives you plenty of flexibility for most trips. For short trips in mild weather, you may not need any special equipment at all. For longer travel or hot climates, a thermal insulated case helps keep the pen in the safe range. Just don’t place the pen directly against an ice pack or frozen gel pack, because that risks freezing the medication.
If you’re flying, pack Wegovy in your carry-on bag. Checked luggage is exposed to extreme temperatures in the cargo hold and can easily freeze or overheat. At the security checkpoint, you’ll need to declare the medication and remove it from your bag for separate screening, along with any cooling accessories. This is routine and won’t cause issues.
Road trips require a bit more planning. Avoid storing the pen in the glove compartment or trunk, where temperatures swing wildly. Keep it in the passenger cabin, ideally in an insulated pouch. If you need to leave the car, take the pen with you rather than leaving it to bake in a parked vehicle.
Wegovy Tablets Are Different
Novo Nordisk also makes a tablet form of Wegovy. The storage rules are completely different. Tablets should be kept at 68°F to 77°F, with brief excursions allowed between 59°F and 86°F. They need to stay in their original bottle to protect against moisture and don’t require refrigeration at all. If you’ve switched to or are considering the tablet form, the 28-day fridge rule doesn’t apply to you.